This invention relates to a socket for the use of an electric part such as an integrated circuit board.
A conventional device of this type, as shown in FIG. 22, comprises a socket body 1 formed in one wall section thereof with a slot 11 for permitting a pivot and bearing pin 10 to be slidingly moved therealong, a plurality of resilient contacts adapted to contact with corresponding contact pieces or leads formed on an electric part 8, a movable stage or support platform 2 which is utilized for supporting the electric part 8 and provided with a cam slot 12 formed in at least one side of the stage and a coil spring 4 for biasing the stage 2 upward, the front end of the pivot and bearing pin 10 being engaged in the cam slot 12 formed in the stage 2. As can be understood from a plan view of FIG. 23 showing the operation of the pivot and bearing pin 10 and the cam slot 12, when the stage 2 is urged downward, the stage 2 is temporarily restrained in an upper or a lower position due to the cooperative action of the pivot and bearing pin 10 and the cam slot 12. At that time, the stage 2 with the cam slot 12 formed therein is vertically and reciprocally moved as a relative motion, whereas the pivot and bearing pin 10 is horizontally and reciprocally moved. When viewed as a relative motion from the stage 2, the pivot and bearing pin 10 is moved along the cam slot 12 to follow a generally unicircular orbit.
With the above-mentioned construction of the conventional device, however, since the pivot and bearing pin 10 is horizontally and reciprocally moved with respect to the vertical and reciprocal movement of the stage 2 for supporting an electric part, resistance of motion is abruptly increased at a place near both ends of the horizontal and reciprocal motion, i.e., at a position where the pivot and bearing pin 10 is displayed from the center line of the electric part supporting stage 2 with respect to the vertical motion of the stage 2, and this resistance acts as a force for inclining the stage 2. As a result, the vertical and reciprocal motion of the stage 2 is not smoothly performed with respect to the horizontal and reciprocal motion of the pivot and bearing pin 10. Thus, the operation of the conventional device is jeopardized.